Grey tank question

[Billeill81]

We have 2024 Avalanche 378bh. While camping for 3 days without sewer connection. We noticed the gray tank for our front bathroom was getting full. We have 3 gray tanks in the full wheel. Do they connect in any way. To help if you fill up one will they overflow to the other.

Thanks,
Bill Williams
2024 Avalanche 378bh

[JRTJH]

Typically, they do not "interconnect" to equalize the tank contents.

Why ?? The "geography" of tank location in most trailers does not permit enough slope for adequate drainage to interconnect the tanks INSIDE the belly area which is usually less than 10" with heat ducts, electrical runs, plumbing PEX runs and black/gray tanks that usually span the entire width of the trailer. And, if the drainage lines were under the trailer, they would freeze during cold weather and cause damage as well as blocking tank drainage...

So, unless, in some isolated floorplans, the gray tanks are co-located side by side, there's no way to get the drainage needed to flow waste water from tank to tank. Some floorplans where the tanks are "for the most part" close together, some owners (me included) have put a terminal cap on the dump outlet and opened the gray valves to get "some of the contents to equalize. But that's an "owner's modified way of using the tanks, not a Keystone OEM build feature.

Honestly, getting 3 days of gray tank capacity in the bathroom is a pretty nice accomplishment on your part. We've got numerous posts where members are dry camping and mid point on day 2, all the tanks are full (except the fresh water tank)...

[GlasNav]

Are the dump valves open with the caps on? Could be equalizing thru the dump lines if they are shared with valves open and caps on.

[bobbecky]

You might have the galley tank drain and the front grey tank drain on the same outlet, and if so, a twist on valve on the outlet could spread the front grey water to the galley tank. With the twist on valve on the common outlet, closed, and the galley and grey drain valves open, you can pick up some capacity in the drain plumbing as well as spreading that grey tank into the galley tank. This might get you an additional day. If you practiced true dry camping, you would not be taking showers, just bare minimum wash cloth baths, and you might easily get a week on those tanks. This is the link to one of the twist on valves. https://www.amazon.com/Valterra-T58-...9700844&sr=8-2

[jxnbbl]

Curious, does this really have 3 gray tanks with 3 separate outlet valves? or are there 3 lights on the "control console"

[NH_Bulldog]

We currently manage 3-4 days on a single 30 gallon grey tank in our TT. If we shower in the trailer, I typically connect the Rhino tote for added capacity.

Even though we don't take delivery of our new 5th wheel for another 6-7 weeks, I do know that it has a grey and black tank for the bathroom and a grey tank for the kitchen. All three tanks have their own dump valves and exit the underbelly in a single drain point. If one grey tank fills before the other, I will be able to add a Valterra termination valve to the main outlet and open both grey tank valves to allow the two tanks to equalize.

[JRTJH]

Originally Posted by NH_Bulldog

We currently manage 3-4 days on a single 30 gallon grey tank in our TT. If we shower in the trailer, I typically connect the Rhino tote for added capacity.

Even though we don't take delivery of our new 5th wheel for another 6-7 weeks, I do know that it has a grey and black tank for the bathroom and a grey tank for the kitchen. All three tanks have their own dump valves and exit the underbelly in a single drain point. If one grey tank fills before the other, I will be able to add a Valterra termination valve to the main outlet and open both grey tank valves to allow the two tanks to equalize.

We do the same. I have a "terminal valve" added to the 3" outlet and keep it closed, open both gray tank valves and "equalize my gray tanks"... These photos are the "OEM factory plumbing tie-in" for the gray tanks. As you can see, the galley gray valve is in the rear (fifth wheel is a rear kitchen floorplan) and the "tie-in" runs under the trailer since there's no way to get a slope inside the belly.

I can, and do equalize during the summer. Any winter camping would not allow me to do that since there would be "gray water" in the 1.5" and the 3" drain lines under the trailer. That would freeze and prevent dumping any tank, black or gray, once the drain lines under the trailer were frozen.

Equalizing is a great way to extend dry camping, but on trailers with any "exposed under trailer drain lines" it becomes a "warm weather option" that can't be used during freezing weather. Even with "protected drain lines" using a terminal valve on the exposed outlet will allow for gray water behind that terminal valve and freeze the valve during cold weather. So pretty much, if there's any exposed plumbing, equalizing becomes a "warm weather option".

[Carl n Susan]

Equalizing grey tanks is a great way to share capacity when boondocking.
But if the shower and kitchen grey tanks are on different levels, as most are in a "drop frame" 5th wheel; I would not do it!!!!

Why you ask? Because you will fill the lower grey tank (usually the shower one) before the kitchen one (everything flows downhill). Once the lower tank is full, then liquid accumulates in the higher tank. OK, that makes sense; why it is an issue?

Only the newest RVs have to Roto-Molded one piece grey tanks. Most of the rest of us have the old two piece tubs with a flat lid that is glued on. The pressure of water in a full lower tank presses on the glued lid. And the pressure increases as the upper tank fills. Eventually the lid on the lower tank will break a glue joint and leak.

[Billeill81]

The kitchen and the Master bathroom share the same drain valve.

[Billeill81]

Originally Posted by jxnbbl

Curious, does this really have 3 gray tanks with 3 separate outlet valves? or are there 3 lights on the "control console"

Yes there are 3 gray tanks. The kitchen and master bathroom share one drain valve. The second bathroom has its own gray and black tanks.

[Richeyb]

We have a 2017 Montana HC with 3 tanks, each have their own valve. But both grey tanks drain through a front drain port. The black through a back port. When draining I normally drain black. A then hook up the hose to the single port in front and open and drain both grey tanks, helping to clean out the hose. At first it was confusing since the bathroom black and grey valves were both located by the back drain port. I finally traced the bathroom grey pipe joining the kitchen grey tank piping for the one exit port under the kitchen slideout.

[Westmonster]

Hi Billieill81, I have the same model except mine is a 2019. Keystone is correct in that there are a total FIVE tanks and none are connected to eachother. Handle 1 in the convenience center is blackwater and is connected to the toilet in the master bathroom.
Gray water handle 1 in the convenience center is for the graywater for the master bathroom (shower and sink). Graywater handle two in the convenience center is for the Kitchen sink graywater. The handles at the rear and under the bunkhouse slideout are for the blackwater tank which is connected connected to sink and toilet together in rear bathroom. The last graywater handle is for the outdoor kitchen. All of my tanks fill up rather quickly with my family of six except for tank that holds the gray water for the outdoor kitchen. When I pull that handle nearly nothing comes out as it is only holding water from the outdoor kitchen sink. My camper is labeled correctly on the outside however labeled incorrectly inside at the wall panel showing the different tank levels. They labeled two out of the five tanks incorrectly but I finally figuered it out. Hope this helps.

[cougar23]

Our Cougar 23MLE has two grey tanks, one for kitchen and one for bathroom. I use Valterra drain caps with a garden hose fitting. Where PERMITTED I use a garden hose connected to the bathroom [shower and sink ] grey tank and drain onto the open ground.

[Sleeve66]

As a general practice, I install Valtera valves at all of my drain connection points. I only use the glue on valves, not the lock-on ones. The reason for this is it protects you when you connect your drain hose. If someone accidentally pulled a valve and then shut it, the tube will be full when you pull the cap off. This makes a mess! I have done this to every RV I have owned. Some RV's have external unprotected drain valves that kids could come along and randomly pull the valve.